1. Probability. There are more women with self esteem, self worth and body issues than not. There are more men who are assholes and jerks than not. Therefore the occurrence of such relationships are greater than positive relationships which means we notice more of those. Sometimes women pick men who are like their dad who parented poorly, because that is what they've seen a relationship as being, that's all they know (if the other relationships surrounding them are such as well).
2. Assholes tend to be overly confident. A reasonable degree of confidence is considered attractive. That's a carryover from cavemen days where men who were successful in feeding their family and procreating were and had to be confident. The "overly confident" trait is however pure arrogance. It isn't always noticeable especially in men who know how to lie and manipulate as they'll balance out that arrogance with false gestures of kindness and caring. That's how some women get entrapped.
3. As I mentioned previously such men typically lie and manipulate, with false stories of their past and present events that aren't within view of those women, thereby creating a "reality" for the woman, who is trusting, and cannot separate lies from truths.
3. Shitty life circumstances. Life's ups and downs can cause women to make wrong decisions thay they otherwise would not make, and go for that wrong kind of guy.
Ergo, it's not all "fascination". There's a lot of predatory manipulation. There are also circumstances.
Unfortunately there are a frighteningly lot of narcissists out there.